Is Your Brain Lying to You?

To identify the causes of confabulation, Asaf Gilboa and his team at the University of Haifa scanned the brains of patients who had suffered damage from a similar kind of aneurysm. Some of them confabulated, but others did not. The scientists then overlapped the scans, with confabulators shown at the left and the truthtellers at the right. Pink indicates that one person had a lesion in that area, and red indicates that all of them did. In the confabulators' brains, the red area covers the ventromedial prefrontal cortex.

On a Monday morning at a home for the elderly in Cologne, Germany, a nurse asked 73-year-old Mr. K. about his weekend. “Oh, my wife and I flew to Hungary, and we had a wonderful time!” he replied. The nurse paused—Mr. K.'s wife had passed away five years ago, and he had not left the home in months. Was he trying to impress her? More likely, Mr. K. was confabulating, a phenomenon in which people describe and even act on false notions they believe to be true.

For confabulators, even physical evidence proving them wrong is not enough to unseat their inaccurate beliefs. Neuropsychologist Morris Moscovitch of the University of Toronto coined the term “honest lying” to describe this condition. Confabulations can consist of wildly untrue statements—claims of being abducted by aliens—but also can consist of memories from long ago, as was the case with Mr. K. They are often autobiographical. Patients easily toggle between rational thought and their false beliefs, unable to differentiate between the two.